This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-118021, filed Apr. 26, 1999, the entire contents of which are incorporated herein by reference.
This invention relates to a camera with a blur reducing function, which can start a photographing operation (a film exposure operation in the case of a camera using a film, and an imaging operation in the case of a digital camera) at a time point at which the camera does not greatly shake, and more particularly to a method for determining whether or not photographing has been started.
There are, so far, lots of proposals for a camera with a blur reducing function, which is adapted to start its exposure operation at a time point at which the camera does not greatly shake.
For example, Japanese Patent Application KOKAI Publication No. 4-175735 discloses a device for preventing camera blur wherein a film exposure operation is started after a period passes, the period being required for attenuation of vibrations that are generated by the mirror-raising operation of a single-lens reflex camera and cause shaking of the camera.
As disclosed in this publication, provision of a waiting period for preventing the influence of vibration occurring when raising a mirror enables the elimination of vibration of the camera. However, the disclosed technique does not sufficiently deal with shaking of the user""s hand, which is practically considered to be a problem.
Further, the period required until the vibration due to the mirror-raising operation sufficiently attenuates is rather long although it differs between different types of cameras. Accordingly, in the disclosed technique, there is a long time lag between the release operation and the actual film exposure.
To deal with xe2x80x9chand shakingxe2x80x9d, various types of cameras are proposed in which the shaking state of the camera is detected before the start of film exposure, and the exposure operation is started where the shaking of the camera is weakened (a blur-reducing/exposure-timing control system).
In this case, the level of shaking is detected when the mirror-raising operation is completed. However, if shake detecting means detects (samples) vibrations that have occurred at the time of the mirror-raising operation, it is possible that an error will occur during shake detection processing (shake estimating operation) to be executed after the mirror-raising operation. This may result in degradation of the blur reducing effect.
Moreover, each camera contains various movable members as well as the aforementioned mirror. The same can be said of a vibration that will occur when driving the movable members.
The present invention has been developed in light of the above, and aims to provide a camera with a blur reducing function, wherein hand shaking is detected without being influenced by vibrations that occur when driving any movable member incorporated in the camera.
According to a first aspect of the present invention, there is provided a camera having a blur reducing function, comprising:
camera control means for controlling an operation of the camera;
shake detecting/computing means for detecting a shake state of the camera and executing computation of the detected shake state;
exposure start determining means responsive to an output of the shake detecting/computing means for executing an exposure start determination so as to reduce a shake level during exposure;
exposure means for starting exposure in accordance with a determination result output from the exposure start determining means;
movable member driving means responsive to an instruction output from the camera control means for driving a movable member incorporated in the camera; and
storage means for storing operation start timing information to be used for the shake detecting/computing means after the movable member is driven by the movable member driving means.
According to a second aspect of the present invention, there is provided a camera having a blur reducing function, comprising:
camera control means for controlling an operation of the camera;
shake detecting/computing means for detecting a shake state of the camera and executing computation of the detected shake state;
exposure start determining means responsive to an output of the shake detecting/computing means for executing an exposure start determination so as to reduce a shake level during exposure;
exposure means for starting exposure in accordance with a determination result output from the exposure start determining means;
movable member driving means responsive to an instruction output from the camera control means for driving a movable member incorporated in the camera; and
storage means for storing operation start timing information to be used for the exposure start determining means after the movable member is driven by the movable member driving means.
According to a third aspect of the present invention, there is provided a camera having a blur reducing function, comprising:
a movable member operable in accordance with a sequence of photography processes;
a memory for storing data relating to an operation period of the movable member;
a sensor for detecting shaking of the camera, after the movable member starts to operate in response to the releasing operation and continues its operation for the operation period stored in the memory; and
a control circuit for instructing to start photography when shake data detected by the sensor satisfies a predetermined determination reference value.
According to a fourth aspect of the present invention, there is provided a camera including:
a sensor for continuously detecting shaking of the camera;
a release switch to be operated for instructing start of photography;
a driving member operable in response to an operation of the release switch; and
a control circuit for starting a determining operation based on the output of the sensor after the driving member operates, and then causing the camera to execute photography when an output of the sensor is lower than a predetermined value.
According to a fifth aspect of the present invention, there is provided a method of reducing, during exposure, shaking of a camera having a sensor for detecting a shake state of the camera, a release switch and a driving mechanism, comprising:
a first step of driving the driving mechanism in response to an operation of the release switch;
a second step of determining the shake state on the basis of an output from the sensor after driving of the driving mechanism is finished; and
a third step of executing exposure at a time point at which a shake level of the camera can be made lower than a reference value, on the basis of the determining result of the second step.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.